The effect of temperature on the structure and function of a cellulose-degrading microbial community.

The purpose of this study was to investigate the effect of temperature on the structure and straw degradation capability of a microbial community grown from wheat straw compost. Two cellulolytic microbial communities, WDC1 and WDC2, were obtained from compost. The communities had been cultured under 50 and 60 °C by continuous enrichment, respectively. The wheat straw degradation capabilities were 45.69 % (WDC1) and 59.5 % (WDC2). By changing the culture temperatures, two new stable communities were obtained: WDC1-6N (WDC1, cultivated at 60 °C for eight generations) and WDC2-5N (WDC2, cultivated at 50 °C for eight generations). The wheat straw degradation capabilities for the new communities were 59.75 and 52.60 %, respectively. The results showed that compared to 50 °C, the wheat straw degradation capability of the communities cultured at 60 °C was stronger. Sequencing of selected denaturing gradient gel electrophoresis (DGGE) bands and analysis of DGGE profiles indicated that the WDC2 structure was significantly different from the structure of WDC1. This was so even though the two communities were enriched from the same compost. With the change of culture temperature, the community structures underwent significant transitions. Included communities were thermophilic, anaerobic bacteria, and any cellulolytic bacteria (e.g., Clostridium thermocellum) that were active and abundant at conditions under 60 °C. These results have the potential to significantly aid in the enrichment of a cellulose-degrading community from the environment and to enhance the community capability to conduct straw biotransformation.